Laser-Processed Protective Glass Micromesh Chips for Acoustic MEMS Sensors

Acoustic microelectromechanical system (MEMS)-based sensors (i.e., MEMS microphones) are often operated in harsh and dusty environments where their main components of thin membranes are prone to damage caused by impacting physical solid objects (e.g., airborne particles and hairs). In this work, glass micromesh chips were fabricated using laser-induced deep etching (LIDE) technology on an 8-inch-wafer-level scale, which can then be potentially used to protect the MEMS microphones from those environmental interferences. During device development, finite element method (FEM) simulation was conducted to optimize the micromesh design and comprehend its effect on the electroacoustic performance of glass mesh-integrated MEMS microphones. Being mounted directly on top of a packaged digital capacitive MEMS microphone sound port, the glass micromesh chip could yield a low signal-to-noise ratio (SNR) loss of (0.65 ± 0.05) dB(A) and a low sensitivity change of (0.11 ± 0.04) dBFS in electroacoustic measurements. Consequently, a high SNR value of the MEMS microphone was able to be maintained at (71.24 ± 0.11) dB(A). Owing to their low production cost on an industrial scale, good environmental protection level, outstanding intrinsic material properties, and high acoustic performance, the developed glass micromesh chips can pave the way for enhancing the robustness of packaged MEMS microphones and being employed in future acoustic sensor technologies.